In multi-circuit electrical connections of the kind used in great variety and numbers in communication systems and other data handling systems, the usual technique for connecting the individual solid or stranded wire conductors to the connector has been to strip the insulation from the end of the conductor and then solder the conductor to a connector contact. This procedure requires considerable skill on the part of the workman making the solder connection, particularly in miniaturized connectors. There is also a tendency to bridge adjacent contacts of the connector, during the soldering operation producing undesired circuit connections.
The conventional soldered connection has long been recognized as requiring improvement or replacement. One alternative, gaining increasing acceptance, entails the use of insulation-piercing terminals for the contact members of the connector; these terminals cut through the insulation and establish an electrical connection to the conductor without preliminary stripping and without the conventional soldering step. The insulation-piercing terminals are usually of forked construction, with cutting edges that penetrate the wire insulation and that also serve as contact jaws that make the necessary electrical connection with the conductor. That is, a forked terminal element on the connector contact serves both as an insulation cutting device and as an electrical contact.
These forked insulation-cutting contacts have a number of disadvantages. Because the contact jaws must be sharp enough to pierce and penetrate the insulation, there is a substantial tendency to cut into the conductor, particularly the individual fragile members of a stranded wire conductor, thereby, weakening the conductor and sometimes disrupting current flow, by disturbance of the skin effect, in high freguency applications. In cutting contact jaws of this kind, the jaws do not open up to the size of the conductor diameter and do not apply an evenly distributed surface pressure to the conductor. Instead, the jaw spacing remains relatively constant, emphasizing scoring of the conductor which may lead to a broken conductor if the connector is subject to vibration in use, and failing to provide the sliding friction between the conductor and the contact jaws that affords optimum electrical contact. The scored part of the conductor is particularly susceptible to corrosion. Moreover, the usual forms of forked insulation-piercing contacts do not provide positive means for keeping the conductors in place, but require separate retainers.